Introduction
Neuropathic pain describes any pain caused by some sort of injury to or dysfunction of one or more nerves. The pain can take a few different forms - it can feel like an electric shock, or like a burning or a cold sensation. It can also be a numbness or tingling or itching sensation. It is sometimes simply referred to as 'nerve pain'.
It is often a chronic condition (i.e. ongoing over a long period of time) and can be challenging to treat successfully.
Some types of neuropathic pain which are covered in more detail elsewhere on this site include…
- Diabetic neuropathy.
- Trigeminal neuralgia.
- Phantom limb pain.
- Post-herpetic neuralgia (linked to shingles) .
- Complex Regional Pain Syndrome.
Approximately 5% of the population of Australia is affected by some form of neuropathic pain.
Causes
The direct cause of neuropathic pain is damage to what is called the 'somatosensory nervous system' which is the component of the nervous system dedicated to the transmission of sensation back to the brain, for example touch and temperature, as well as 'nociception', which is the transmission of pain signals to the brain.
The following factors are known to cause neuropathic pain…
- Injury (including injury to the spinal cord) .
- Diabetes.
- Compressed ('trapped') nerve/s.
- Tumour or osteophyte (bone spur) putting pressure on a nerve.
- Infections (e.g. shingles, HIV / AIDS).
- Other medical conditions e.g. stroke, multiple sclerosis, fibromyalgia.
- Chemotherapy.
- Vitamin deficiency (especially B1 'thiamine' and B12).
Symptoms
As described above, neuropathic pain generally involves the following symptoms…
- ‘Electric shock’ type or shooting type of pain.
- Burning / cold sensation.
- Numbness / tingling.
- Itching sensation.
- Pain that gets worse at night time.
- Pain may be constant or may come and go.
- Hypersensitivity i.e. increased sensitivity to temperature or touch, where even a light touch can be painful.
Tests / Diagnosis
The first step in the diagnosis of neuropathic pain is a review of medical history and of current symptoms. The next step is an examination where the nerves in the affected areas are checked, by for example testing sensitivity to various types of touches and light pinpricks, along with sensitivity to different temperatures.
If an initial diagnosis flags a possible neuropathic cause, further tests may be recommended, such as blood tests, a nerve conduction study (to test if there is any nerve dysfunction) and an MRI scan. In some cases, a biopsy (tissue sample) may also be recommended.